Recently, a head-mounted display (HMD) mounted to a head of a user has been known. Theoretically, the head-mounted display includes a configuration to magnify an image displayed on a small display element with a magnification optical system and to lead the image to an eye of an observer. That is, the head-mounted display is configured to optically magnify an image displayed on a display element and to make a user observe the image as a magnified virtual image.
For example, as illustrated in FIG. 14(a), in such a head-mounted display, when a gap is generated between a center of an optical system and a position of an eye of an observer, a video image influences a conformable image observation. In this case, for example, according to a gap amount, a color shift is caused, contrast is decreased, or image distortion is caused. Note that in FIG. 14(b), a case where there is no gap between a center of the optical system and a position of the eye of the observer is illustrated.
For example, in Patent Document 1, a head-mounted display in which an optical system is configured in a movable manner and a positional gap between an eye of an observer and the optical system can be corrected by a manual movement adjustment of the optical system by the observer has been proposed.